Electrical conductors are used in directional drilling of wells and in well logging systems to convey electrical signals to and from downhole tools. In directional and/or horizontal well drilling, an electrical conductor or wireline is connected between the steering tool and well surface equipment, the wireline extending through the interior of the drill string. The wireline transmits electrical signals to and from the downhole tools connected therewith.
It is desirable or necessary from time to time to connect, disconnect and/or reconnect the downhole wireline. It may be necessary to connect, disconnect, and/or reconnect logging instruments. It may be necessary to disconnect downhole wireline to allow drill string rotation and to reconnect same. Disconnecting and reconnecting are required incident to inserting additional drill pipe or removing drill pipe from the drilling string.
Insulation of the electrical contact and receptacle from the drilling string fluids is necessary due to the conductivity of brine or brackish fluids associated with drilling operations. If not adequately sealed, the electrically conductive brackish liquid interferes with the transmission of electrical signals between the surface and the downhole tool and accelerates corrosion.
Disadvantages of the prior art include failure to effectively seal electrically-conductive brine away from the receptacle-contact interface. Another disadvantage of the prior art is failure to effectively seal the conductor from other metal surfaces of the wet connect seal, resultive in infiltration of brine between the conductor and the wet connect body thereby allowing electrical conduction between the conductor and the wet connect body. Current technology requires insertion of a quantity of grease to protect electrical connections to the extent possible from brackish liquids.
Ramsey et al. U.S. Pat. No. 4,588,243 discloses a make and break mechanical and electrical latch sub-assembly providing for connection of a wireline. The assembly includes a male probe and a female receiver, the female receiver including a pair of spaced rings extending from the female receiver, the spaced rings first receiving the male probe and orienting the male probe toward the smaller orifice provided in the receiver. The male probe includes inclined shoulders to align the smaller forward extension of the male probe with the smaller orifice provided in the female receiver.
Lenhart et al. U.S. Pat. No. 5,131,464 discloses a connectable and releasable electrical wet connect for transmitting electrical signals including telescoping male and female electrical connectors. The male member includes a support shoulder for supporting the wet connect in the drill string, a passageway for flow of fluids through the drill string, an electrical contact extending through the male member, a tapered and insulating seal positioned below the electrical contact, and a tapered and insulating female seal positioned below the electrical contact for co-acting with the male seal for insulating the engaged receptacle and contact from fluid in the drill string.
It is an object of the present invention to provide an improved wireline wet connect for use in brackish environments.
It is an object of the present invention to provide a wireline wet connect providing for improved electrical insulation between the electrical contact-receptacle interface and the surrounding environment.
It is an object of the present invention to provide a wireline wet connect having an improved connection between the electrical receptacle and the electrical contact.
It is an object of the present invention to provide a wireline wet connect having improved insulation characteristics and capable of telescopic self-alignment.
The foregoing and other objects of the present invention are accomplished by a wireline wet connect for releasable connection of an electrical contact and receptacle in a well drill string, the wet connect including co-axial connecting male and female connecting assemblies. The male connecting assembly includes a central upwardly-extending conductor rod having an electrical contact at its upward end, the contact being received in a receptacle provided in the female connecting assembly. The conductor rod is contained with and surrounded by an insulating sleeve. The conductor rod and insulating sleeve are contained along a portion of their length within a cylindrical body. The cylindrical body includes inclined shoulders for supportably receiving an external retainer sleeve provided on the female connecting assembly. A three-finned landing member is provided exterior of the cylindrical body of the male connecting assembly for supporting the wet connect on a drill string collar. A lower connector sleeve is releasably engaged with the cylindrical body, the lower connector sleeve engaging a wireline rope socket. The female connecting assembly comprises a cylindrical outer body surrounding an insulating sleeve, the insulating sleeve releasably contained within the outer body by a retainer sleeve, the retainer sleeve having a lower inclined collar receivable on a shoulder of the cylindrical body. An electrical receptacle and a conductor are contained interior of the insulating sleeve. A spring is provided between the receptacle and the electrical conductor, the spring biasing the receptacle toward the conductor rod contact. Concentric ring seals are provided inwardly of the insulating sleeve, the said seals engaging the conductor rod insulating sleeve below the contact and providing electrical insulation between the electrical contact and receptacle and fluids exterior of the said seals. The seals are constructed so as to provide an outer sealing ring for sealing contact with the insulating sleeve, an inner sealing ring for sealing contact with the conductor rod insulating sleeve, and a flexible connection between the outer sealing ring and the inner sealing ring. Upon connection of the male connecting assembly with the female connecting assembly, electrical connection of the conductors is established, the electrically conductive brine being sealed within insulated annular voids and sealed external of the said conductors, receptacle and contact.